Boffins at Toshiba’s Cambridge Research Labs have developed a technique for turbo-charging the speed of quantum cryptography transmissions.
Quantum key distribution (QKD) systems currently operate at dial-up rates of less than 10 kbps for 20km, making them suitable only for point-to-point links. The Cambridge researchers have …

@Alastair Smith

Nice link - it does conclude "However, it should be possible to solve the problem completely by redesigning the vulnerable detector".

The NSA won't allow this to be deployed. Recent UK legislation has made refusal to unencrypt when requested by the relevant authorities a criminal offense, so perhaps the authorities are predicting that one day they won't easily be able to eavesdrop. Most people don't even encrypt/sign email so there little concern but education and increased criminal intellect will mean the public at large might get wise (say by 2020?).

Anon because I mentioned the NSA (and I always like using Anon)... Echelon is still active...

Re: NSA won't allow...

As I understand it, quantum encryption only lets you encrypt data in transit. You'd still need some other method to *keep* it secure once it reached the other end. If so, the NSA won't care how secure the wire is.

No, the real problem with quantum cryptography when compared with the classical variety is that our faith in the former stems from a conviction that there will be no new developments in physics (rather than mathematics) that undermine the technique. Imagine betting the farm (or the bank) at the end of the 19th century on future physics just being more of the same.

Quantum DoS

Surely this system has one critical flaw. If an eavesdropper affects the transmission in a way that would require a re-transmission then surely it opens a new type of DoS attack. All you need to do to stop any communication is to constantly eavesdrop on the channel - Quantum DoS!

Re: NSA won't allow...

To follow up my own comment ("You'd still need some other method to *keep* it secure once it reached the other end.") if you *had* another (secure) method of securing your data then why would be interested in encrypting it by a different (and unproven) method over the wire? Particularly if, as Griffter observes, the method is particularly prone to DoS attacks which (the payload being already secure) are the only remaining form of attack against your communication.

Point to Point?

Er, I'm not an expert in this but I thought quantum crypto was necessarily point to point? By reading the photons you drop them into a known state, which means they can only be read once. It's why quantum crypto can't be intercepted without detection.

Yes, it's incredible secure, but only so long as your network doesn't require any switches or routers, which kind of limits its application. 10kps or 1000kpbs, if you're limited to 25km of point to point it's really not going to make a great deal of difference.

Hmm

Although this is rather impressive (despite the research behind it having been available for a long time), it's not really "quantum cryptography". It's using quantum physics to distribute a value. The cryptography used is still the same rsa/dsa/shared key/whatever. Thus surely it's still susceptible to the same attacks - if quantum computers "make it", then brute-force attacks on ciphertexts become simple.

Of course, the problem is lessened by using the keys as one-time pads, but still, cracking messages is possible, surely.